1. Field of The Invention
The present invention relates generally to dome type switches for use on, for example, a control panel forming part of a video or data recorder or other such apparatus, and more particularly to a specifically designed illuminated dome type switch.
2. Description of the Related Art
Dome type switches, or merely dome switches as they will be referred to herein, are well known in the art. Even illuminated dome switches are known in the art. One such commercially available arrangement is illustrated in prior art FIG. 1. This arrangement which is generally indicated by the reference numeral 10 is shown including two dome switches 12 supported on a printed circuit board 14 with an incandescent lamp, light emitting diode or like light source 16 within a diffuser block 17 located between the two switches for simultaneously illuminating both. Each of the dome switches 12 includes a dome 18 and a keycap 20. The dome, which is shown mounted on the top surface of printed circuit board 14, is constructed of stainless steel or like electrically conductive, resilient material and is designed to resiliently move between a biased OFF or open position and a depressed ON or closed position, both of which are illustrated in FIG. 1.
Each of the keycaps 20 includes an upper main body 22 constructed of transparent or at least translucent material and a downwardly projecting actuator 24 disposed centrally below its associated main body portion 22. As illustrated in FIG. 1, each keycap is positioned immediately above a cooperating dome 18 within a cooperating opening 26 defined by an outer facia 28 forming part of the overall control panel 10. Means not shown, for example, a resilient boot, is disposed within each of the openings 26 in order to support its associated keycap for movement, between a biased raised position such that the keycaps actuator 24 does not depress dome 18 and a depressed lower position which, in turn, causes its actuator to depress the underlying dome.
Depression of a dome 18, as illustrated by the dome on the right in FIG. 1, closes a cooperating circuit on the PC board. Typically, the dome need be depressed only momentarily in order to close the circuit after which the circuit can again be opened by subsequently momentarily depressing the same keycap.
In the case of prior art dome type switches generally, it is very difficult to adequately and uniform illuminate individual keycaps. This is because the keycaps are typically disposed directly over their respective domes, as illustrated in FIG. 1. Thus, an attempt to illuminate a keycap typically takes the form of an incandescent lamp, LED or like light source located to one side of the switch, as shown. As will be described in more detail hereinafter, the present invention overcomes the problem just described by supporting a dome and a light source side by side, as in the case of the arrangement illustrated in FIG. 1. However, in accordance with the present invention, as will be seen, the keycap is disposed directly over the light source rather than over the dome, the latter being positioned to one side of the keycap. Nevertheless, the keycap is specifically designed to actuate its dome in the same reliable manner as the prior art. However, by placing the light source directly under the keycap, rather than to one side, it more efficiently and uniformly lights up the keycap.